Convergent spray apparatus is currently available and has been, for example, disclosed in U.S. Pat. No. 5,565,241 granted on Oct. 15, 1996 to Mathias et al entitled "Convergent End-Effector" and U.S. Pat. No. 5,307,992 granted on May 3, 1994 to Hall et al entitled "Method And System For Coating A Substrate With A Reinforced Resin Matrix" both of which include the inventor of the present invention, Jack G. Scarpa, as a named co-inventor and both of which are commonly assigned to USBI, Co. The U.S. Pat. Nos. 5,565,241 and 5,307,992 patents, supra, disclose apparatus for providing a convergent spray for applying the coating of reinforced resins matrix to a substrate is a spray nozzle that includes a centrally disposed orifice and a plurality of circumferentially spaced orifice(s) surrounding the center orifice for creating an atomizing zone. Included are other orifices radially spaced outwardly from these orifices which are used for shaping the spray. Reinforcing material is introduced to the resin through the aft end of an encircling chamber or manifold that surrounds the spray nozzle and is designed to feed the reinforcing material to the liquid resin. Pneumatic eductor lines for conducting compressed air are utilized to transport the materials to the substrate.
While these techniques have been described in the literature and are commercially available, there are no commercially available spray applications that can convergently apply a foaming thermal/acoustic insulation containing solid fillers.
I have found that I can provide a foaming thermal/acoustic insulation that contains solid fillers by combining a three part foaming resin system by supplying individually the mixed foaming resin and the selected solid fillers into a convergent nozzle. And then dynamically combines these ingredients externally of the spray nozzle through a convergent process. The system of the present invention contemplates heating the three part foaming resin in separate pressure containers in order to reduce the viscosity and allow for easier flow through metered liquid handling sub-systems prior to entering the dynamic mixing chamber in the convergent nozzle.
This invention contemplates the use of a three part foaming resin system. Each part uses a separate pump and flow metering system. Part A epoxy resin and part B catalyst are pumped and metered separately to the resin mix chamber at the end of the convergent gun A third part foaming agent and surfactant is also pumped and metered separately to the mix chamber. All three materials are mixed in mix chambers and then atomized and combined with dry fillers in the convergent zone.
The convergent spray technique of this invention can be utilized in a multitude of applications of which several are listed hereinbelow and it is to be understood that this invention is not limited to the applications enumerated hereinbelow:
1) Thermal protection system (TPS) for application of aerospace vehicles for either thermal insulation or ablative insulation functions; PA1 2) Smoke and flame retardant foam insulation products which could replace fiberglass insulation as for example in automotive, boats, trains and the like; PA1 3) Acoustic insulation using recycled rubber as a filler; PA1 4) structurally reinforced foam with greater stiffness than conventionally applied systems; and PA1 5) cryogenic insulating systems for aerospace vehicles. PA1 1. Adding a functional filler, such as granular cork and glass micro spheres, in high concentrations to sprayable foams for TPS type materials; PA1 2. Controlling the thickness of the applied coating by virtue of either the process or the formulation; PA1 3. Matching dimensions of area to be coated on the substrate, thereby minimizing waste and over spray; PA1 4. Controlling the composition of the coating by controlling both filler and resin material independently; PA1 5. Providing significantly reduction in waste and hazardous materials; PA1 6. Providing flexibility in substituting different resins and fillers; and PA1 7. Enhancing the strength and elongation of the coating.
Without imposing any limitations, this invention has the ability of: